Expansion method, method for manufacturing semiconductor device, and semiconductor device

ABSTRACT

An embodiment of the present invention relates to an expansion method comprising: a step (I) of preparing a laminate having a semiconductor wafer in which modified sections have been formed along intended cutting lines, a die bonding film and a dicing tape, a step (IIA) of expanding the dicing tape with the laminate in a cooled state, a step (IIB) of loosening the expanded dicing tape, and a step (IIC) of expanding the dicing tape with the laminate in a cooled state, dividing the semiconductor wafer and the die bonding film into chips along the intended cutting lines, and widening the spaces between the chips.

TECHNICAL FIELD

Embodiments of the present invention relate to an expansion method, amethod for manufacturing a semiconductor device, and a semiconductordevice.

BACKGROUND ART

In recent years, remarkable progress has been made in terms of reducingthe thickness and size of semiconductor chips. In particular, thesemiconductor chips installed in IC cards such as memory cards and smartcards require a chip having a thickness of not more than 75 μm and asize of not more than 10 mm×10 mm. It is thought that as the demand forIC cards increases in the future, the requirement for small, thin chipswill continue to grow.

Semiconductor chips are usually obtained by processing a semiconductorwafer to a prescribed thickness in a back grinding step or etching stepor the like, and subsequently dividing the semiconductor wafer intoindividual chips in a dicing step. In the dicing step, a blade cuttingmethod in which the semiconductor wafer is cut with a dicing blade isgenerally used. In the blade cutting method, minute defects (alsoreferred to as “chipping”) are sometimes formed on the semiconductorchip as a result of the cutting resistance generated during the cuttingprocess. This occurrence of chipping not only impairs the externalappearance of the semiconductor chip, but depending on the degree ofchipping, can sometimes cause damage to the circuit pattern on thesemiconductor chip, and has recently been recognized as an importantproblem. In semiconductor chips that have been reduced in thickness andsize, the permissible level of chipping is particularly stringent. It isexpected that in the future, as further reductions are made in thethickness and size of semiconductor chips, the problem of chipping willbecome more critical.

The stealth dicing method is another method that can be used in thedicing step. The stealth dicing method is a method particularly suitedfor cutting ultra thin semiconductor wafers, and it is known that thestealth dicing method is able to suppress chipping. The stealth dicingmethod is performed in the following manner.

In one specific example of the stealth dicing method, first, a laserbeam is irradiated onto the semiconductor wafer so that the focal pointof the laser beam is located inside the interior of the semiconductorwafer, thereby forming a brittle modified section inside thesemiconductor wafer as a result of multiphoton absorption. By moving theirradiation position of the laser beam along the lines which indicatethe positions where the semiconductor wafer is to be divided intoindividual semiconductor chips (also referred to as “intended cuttinglines”), modified sections (also referred to as “dicing lines”) can beformed along the intended cutting lines. Subsequently, a dicing tape isaffixed to the rear surface of the semiconductor wafer (the surface onwhich no circuit is formed), and the dicing tape is then expanded. As aresult, external stress is applied to the semiconductor wafer, and thesemiconductor wafer cleaves along the intended cutting lines, thusdividing the wafer into individual semiconductor chips and widening thespaces between the semiconductor chips.

The step of expanding the dicing tape is usually called an expansionstep. The expansion step is a step that is generally conductedregardless of whether the dicing step is performed using the bladedicing method or the stealth dicing method. When the dicing step isperformed using the blade dicing method, the semiconductor wafer isdivided into semiconductor chips using the dicing blade, and theexpansion step is then performed to widen the spaces between thesemiconductor chips. In this case, the expansion step is conductedmainly for the purpose of facilitating pickup of the semiconductorchips. However, when the dicing step is performed using the stealthdicing method, then as described above, the expansion step functions asa step for dividing the semiconductor wafer in which the dicing lineshave been formed into individual semiconductor chips. Further, inaddition, the expansion step also functions as a step for widening thespaces between the divided semiconductor chips. Examples of the methodsand apparatus used in the expansion step are disclosed in PatentLiteratures 1 to 3 and the like.

CITATION LIST Patent Literature

PLT 1: JP 2005-109044 A

PLT 2: JP 2005-057158 A

PLT 3: JP 2009-253071 A

SUMMARY OF INVENTION Technical Problem

Conventionally, the bonding between semiconductor chips and adherendssuch as support members has mainly used silver paste. However, whensilver paste is used with a semiconductor chip that has been reduced inthickness and size, paste protrusion, difficulties in controlling thepaste thickness, wire bonding problems caused by tilting of thesemiconductor chip, and the occurrence of voids and the like are issueswhich cannot be ignored. These issues are particularly severe in modernsemiconductor devices that require high integration of the semiconductorchips and miniaturization of support members.

Accordingly, in recent years, film-like die bonding materials known asdie bonding films have increasingly been used for the bonding ofsemiconductor chips and adherends. When a die bonding film is used, thedie bonding film and a dicing tape are affixed in that order to the rearsurface of the semiconductor wafer. By subsequently cutting thesemiconductor wafer and the die bonding film at the same time during thedicing step, semiconductor chips with a die bonding film affixed theretoare obtained. The thus obtained semiconductor chips can be bonded toadherends via the die bonding film.

When the semiconductor wafer and the die bonding film are cut using thestealth dicing method, the expansion step requires that the die bondingfilm is cut together with the semiconductor wafer in which the dicinglines have been formed. By performing the expansion step, thesemiconductor wafer and the die bonding film are then divided intoindividual semiconductor chips (also referred to as “chips”) each havinga die bonding film affixed thereto.

In light of these circumstances, an embodiment of the present inventionhas an object of providing an expansion method that enables asemiconductor wafer and a die bonding film to be cut favorably. Further,by employing this expansion method, other embodiments of the presentinvention have objects of providing a method for manufacturing asemiconductor device which enables efficient manufacture of thesemiconductor device, and a semiconductor device obtained using thismanufacturing method.

Solution to Problem

One embodiment of the present invention relates to an expansion methodcomprising: a step (I) of preparing a laminate having a semiconductorwafer in which modified sections have been formed along intended cuttinglines, a die bonding film and a dicing tape; a step (IIA) of expandingthe dicing tape with the laminate in a cooled state; a step (IIB) ofloosening the expanded dicing tape; and a step (IIC) of expanding thedicing tape with the laminate in a cooled state, dividing thesemiconductor wafer and the die bonding film into chips along theintended cutting lines, and widening the spaces between the chips.

Further, another embodiment of the present invention relates to a methodfor manufacturing a semiconductor device comprising: a step (I) ofpreparing a laminate having a semiconductor wafer in which modifiedsections have been formed along intended cutting lines, a die bondingfilm and a dicing tape; a step (II) of expanding the dicing tape,dividing the semiconductor wafer and the die bonding film into chipsalong the intended cutting lines, and widening the spaces between thechips; a step (III) of picking up a chip from the dicing tape; and astep (IV) of die bonding the chip to an adherend, wherein the step (I)and the step (II) are performed using the expansion method of theembodiment described above.

Yet another embodiment of the present invention relates to asemiconductor device having an adherend, and a chip bonded to theadherend, wherein the semiconductor device is manufactured using themethod for manufacturing a semiconductor device according to theembodiment described above.

The disclosure of the present application is related to the subjectmatter disclosed in prior Japanese Application 2012-282785 filed on Dec.26, 2012, the entire contents of which are incorporated herein byreference.

Advantageous Effects of Invention

One embodiment of the present invention is able to provide an expansionmethod that enables a semiconductor wafer and a die bonding film to becut favorably. Further, other embodiments of the present invention areable to provide a method for manufacturing a semiconductor device thatenables efficient manufacture of the semiconductor device, and asemiconductor device obtained using this manufacturing method.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram illustrating one embodiment of theexpansion method.

FIG. 2 is a schematic diagram illustrating one embodiment of a step ofobtaining a semiconductor wafer in which modified sections have beenformed along intended cutting lines.

FIG. 3 is a schematic diagram illustrating one embodiment of a step ofaffixing a die bonding film to a semiconductor wafer.

FIG. 4 is a schematic diagram illustrating one embodiment of a step ofaffixing a dicing tape to a die bonding film.

FIG. 5 is a schematic diagram illustrating one embodiment of a step ofaffixing a dicing-die bonding integrated sheet to a semiconductor wafer.

FIG. 6A is a schematic diagram illustrating one embodiment (steps (Ia)to (IIa)) of the expansion method.

FIG. 6B is a schematic diagram illustrating one embodiment (steps (IIb)to (IIc)) of the expansion method.

FIG. 7A is a schematic diagram illustrating one embodiment (steps (Ia′)to (IIa′)) of the expansion method.

FIG. 7B is a schematic diagram illustrating one embodiment (steps (IIb′)to (IIb′) of the expansion method.

FIG. 8 is a schematic diagram illustrating one embodiment of a laminate.

FIG. 9 is a flow chart illustrating one embodiment of the expansionmethod.

FIG. 10 is a schematic diagram illustrating one embodiment of a step ofpicking up a chip from the dicing tape.

FIG. 11 is a schematic diagram illustrating one embodiment of a step ofdie bonding a chip to an adherend.

FIG. 12 is a schematic diagram illustrating one embodiment of asemiconductor device.

FIG. 13 is a schematic diagram illustrating one embodiment of asemiconductor device.

FIG. 14A is a schematic diagram illustrating one embodiment of a dicingtape used for evaluating the amount of expansion and the expansionratio.

FIG. 14B is a schematic diagram illustrating a dicing-die bondingintegrated sheet used in evaluations in Example 1 and ComparativeExample 1.

FIG. 15 is a photograph illustrating a semiconductor wafer followingexpansion in Example 2.

FIG. 16 is a photograph illustrating a semiconductor wafer followingexpansion in Example 3.

FIG. 17 is a photograph illustrating a semiconductor wafer followingexpansion in Comparative Example 2.

FIG. 18 is a schematic diagram illustrating one example of aconventional expansion method.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention are described below using thedrawings. In the drawings, the same members are labeled with the samenumbers, and duplicate descriptions are omitted.

First Embodiment

The first embodiment relates to an expansion method for cutting asemiconductor wafer and a die bonding film along intended cutting linesto divide the wafer into chips, and expanding the spaces between thechips.

When cutting a semiconductor wafer and a die bonding film, the expansionstep is generally performed at low temperature from the viewpoint ofimproving the fracture properties of the die bonding film. However, evenwhen the expansion step is performed at low temperature, thesemiconductor wafer and the die bonding film can sometimes not be cut.FIG. 18 is a schematic diagram illustrating one example of aconventional expansion method, and shows an example in which asemiconductor wafer 1 and a die bonding film 2 are not cut. In FIG. 18,a dicing tape 3 to which the semiconductor wafer 1 and the die bondingfilm 2 have been laminated is expanded by pushing the dicing tape 3upward under cooling using an expansion stage 10 fitted with a coolingdevice.

The inventors of the present invention thought that one of the reasonsfor failure to cut the semiconductor wafer and the die bonding film wasdue to the extensibility of the dicing tape in a low-temperature state.The extensibility of the dicing tape decreases at low temperature, andit is thought that the amount of expansion of the dicing tape becomesinsufficient, resulting in a reduction in the external force that can beapplied to the semiconductor wafer and the die bonding film.Accordingly, the expansion method of the present embodiment is providedas a method for improving the extensibility of the dicing tape in alow-temperature state.

In other words, by performing the expansion step at low temperature,although the fracture properties of the die bonding film improve, theextensibility of the dicing tape decreases, and therefore a satisfactoryexternal force cannot be imparted to the semiconductor wafer and the diebonding film. In contrast, the present embodiment is an expansion methodin which the extensibility of the dicing tape in a low-temperature stateis improved by a simple method, thus enabling the semiconductor waferand the die bonding film to be cut favorably.

The first embodiment relates to an expansion method comprising: a step(I) of preparing a laminate having a semiconductor wafer in whichmodified sections have been formed along intended cutting lines, a diebonding film and a dicing tape; a step (IIA) of expanding the dicingtape with the laminate in a cooled state; a step (IIB) of loosening theexpanded dicing tape; and a step (IIC) of expanding the dicing tape withthe laminate in a cooled state, dividing the semiconductor wafer and thedie bonding film into chips along the intended cutting lines, andwidening the spaces between the chips. FIG. 1 is a schematic diagramillustrating the first embodiment. The laminate is shown in across-sectional view. Unless specifically stated otherwise, thedescription relating to the first embodiment, where applicable, alsoapplies to the other embodiments described below.

The present embodiment has the steps (I) to (IIC) in this order. Theembodiment may also include other optional steps before or after eachstep, such as a step of detaching a protective sheet, a transport step,or an inspection or verification step. The steps (IIA) to (IIC) arepreferably performed consecutively.

(Step (I))

As illustrated in FIG. 1, first, a laminate 6 having a semiconductorwafer 1 in which modified sections 5 have been formed along intendedcutting lines 4, a die bonding film 2 and a dicing tape 3 is prepared(step (I)). Conventionally known methods can be used as the method forobtaining the laminate 6. One example of the method for obtaining thelaminate 6 is described below.

Examples of the semiconductor wafer include wafers formed from siliconsuch as single-crystal silicon or polycrystalline silicon, variousceramics, sapphire, or compound semiconductors such as gallium nitrideor gallium arsenide. Other semiconductor wafers besides those listedabove can also be used.

There are no particular limitations on the thickness or size of thesemiconductor wafer. From the viewpoint of reducing the occurrence ofchipping, the thickness of the semiconductor wafer is, for example,preferably 25 μm or greater. Further, from the viewpoint of enablingpackage miniaturization, the thickness of the semiconductor wafer is,for example, preferably not more than 100 μm, more preferably not morethan 75 μm, and still more preferably 50 μm or less. From the viewpointof improving productivity, the diameter of the semiconductor wafer is,for example, preferably at least 200 mm, and more preferably 300 mm orgreater.

The “intended cutting lines” refer to the lines along which it isintended to divide the semiconductor wafer. Chips are obtained bycutting the semiconductor wafer and the die bonding film along theseintended cutting lines. The thus obtained “chips” include asemiconductor chip and an individual piece of the die bonding filmbonded to the semiconductor chip.

Modified sections are formed in advance in the semiconductor wafer alongthe intended cutting lines. These “modified sections” are preferablybrittle modified sections formed by irradiating a laser beam onto thesemiconductor wafer so that the focal point of the laser beam is locatedinside the interior of the semiconductor wafer. FIG. 2 is a schematicdiagram illustrating one embodiment of the step of forming the modifiedsections 5 along the intended cutting lines 4 in the semiconductor wafer1. The irradiation of the laser beam onto the semiconductor wafer 1 maybe performed from the upper surface of the semiconductor wafer 1, namelythe surface 1 a on which a circuit is formed, or may be performed fromthe rear surface of the semiconductor wafer, namely the surface 1 b onwhich no circuit is formed.

The method used for forming the modified sections in the interior of thesemiconductor wafer 1 may employ the method disclosed in JP 2002-192370A or JP 2003-338467 A. Examples of the apparatus that can be used in thelaser beam irradiation include a laser dicing apparatus “Mahoh DicingMachine” (manufactured by Tokyo Seimitsu Co., Ltd.) and a laser dicingsaw “DFL7360” (manufactured by DISCO Corporation).

Examples of the conditions used when using the laser dicing apparatus“Mahoh Dicing Machine” (manufactured by Tokyo Seimitsu Co., Ltd.) areshown below. By irradiating the laser beam onto the upper surface of thesemiconductor wafer under the conditions described below, with the focalpoint of the laser beam located inside the interior of the semiconductorwafer, and then moving the laser beam along the intended cutting lines,modified sections can be formed inside the semiconductor wafer. Themodified sections are preferably melt treatment regions formed bylocalized heating and melting of the interior of the semiconductor waferupon multiphoton absorption.

(Laser Processing Conditions)

(A) Semiconductor wafer: silicon wafer (thickness 75 μm, outer diameter12 inches (300 mm))

(B) Laser beam source: semiconductor laser-excited Nd:YAG laser

-   -   Wavelength: 1064 nm    -   Laser spot surface area: 3.14×10⁻⁸ cm²    -   Oscillation form: Q-switch pulse    -   Repeat frequency: 100 kHz    -   Pulse width: 30 ns    -   Output: 20 μJ/pulse    -   Laser beam quality: TEMOO    -   Polarization characteristics: linear polarization

(C) Condenser lens magnification: 50-fold

-   -   NA: 0.55    -   Transmittance of laser beam wavelength: 60%

(D) Movement speed of mount on which semiconductor wafer is mounted: 100mm/second

There are no particular limitations on the spacing between the intendedcutting lines. The obtained chips will have a size determined by thespacing between the intended cutting lines.

The die bonding film is an adhesive film that is used when mounting asemiconductor chip to a semiconductor chip-mounting support member suchas a lead frame or an organic substrate, or when laminatingsemiconductor chips together. The die bonding film contributes tosimplifying and improving the throughput of the die bonding step. Acommercially available product can be used as the die bonding film. Inthe laminate, the die bonding film is usually larger than thesemiconductor wafer, and typically has a circular or substantiallycircular shape.

There are no particular limitations on the thickness and size of the diebonding film. From the viewpoint of preventing detachment from thesemiconductor wafer, the diameter of the die bonding film is, forexample, preferably not more than 350 mm, more preferably not more than335 mm, and still more preferably 320 mm or less. Although not beingspecific restrictions, these sizes are particularly suited tosemiconductor wafers having a diameter of 300 mm.

The dicing tape is a tape which protects and secures the semiconductorwafer in the semiconductor wafer dicing step, and is then used forholding the semiconductor chip in subsequent steps. A commerciallyavailable product can be used as the dicing tape. In the laminate, thedicing tape is usually larger than the die bonding film, and typicallyhas a circular or substantially circular shape.

There are no particular limitations on the thickness and size of thedicing tape. From the viewpoints of operability and processability, thethickness of the dicing tape is, for example, preferably 70 μm orgreater.

The die bonding film and the dicing tape are also available commerciallyin the form of a dicing-die bonding integrated sheet in which the twoitems are stuck together. By using a dicing-die bonding integratedsheet, the affixing of the die bonding film and the dicing tape to therear surface of the semiconductor wafer can be performed in a singleoperation. Using a dicing-die bonding integrated sheet contributes to ashortening of the manufacturing steps for a semiconductor device, and animprovement in the handling properties of the thin wafer.

The laminate having the semiconductor wafer, the die bonding film andthe dicing tape usually has at least the semiconductor wafer, the diebonding film and the dicing tape provided in that order. Besides theselayers, the laminate may also have other optional layers such as aprotective tape for protecting the semiconductor wafer surface, or asupport film for supporting the dicing tape. Further, the die bondingfilm and the dicing tape may each be formed from a single layer or aplurality of layers.

In terms of facilitating recognition of those sections in which the diebonding film has not been cut following expansion, the die bonding filmand the dicing tape preferably differ in terms of transparency or colortone or the like.

The laminate can be obtained, for example, by affixing the die bondingfilm to the rear surface of the semiconductor wafer, and then affixingthe dicing tape to the die bonding film. FIG. 3 is a schematic diagramillustrating one embodiment of a step of affixing the die bonding film 2to the semiconductor wafer 1, whereas FIG. 4 is a schematic diagramillustrating one embodiment of a step of affixing the dicing tape 3 tothe die bonding film 2.

There are no particular limitations on the temperature and the pressurewhen affixing the die bonding film to the semiconductor wafer, and thesevalues may be determined as appropriate, with due consideration of theadhesiveness and the like of the die bonding film.

There are no particular limitations on the temperature and the pressurewhen affixing the dicing tape to the die bonding film, and these valuesmay be determined as appropriate, with due consideration of theadhesiveness and the pressure-sensitive adhesiveness and the like of thedie bonding film and the dicing tape.

Furthermore, when a dicing-die bonding integrated sheet is used, thelaminate can be obtained by affixing the die bonding film-side surfaceof the dicing-die bonding integrated sheet to the rear surface of thesemiconductor wafer. FIG. 5 is a schematic diagram illustrating oneembodiment of a step of affixing a dicing-die bonding integrated sheet 8to the semiconductor wafer 1.

There are no particular limitations on the temperature and the pressurewhen affixing the dicing-die bonding integrated sheet to thesemiconductor wafer. From the viewpoint of improving the adhesion withthe semiconductor wafer, the temperature during the affixing process is,for example, preferably at least 50° C., and from the viewpoint of theheat resistance of the dicing tape, is preferably not more than 80° C.

The formation of the modified sections inside the interior of thesemiconductor wafer can be performed before affixing the die bondingfilm to the semiconductor wafer, after affixing the die bonding film tothe semiconductor wafer, or after affixing the die bonding film and thedicing tape, or the dicing-die bonding integrated sheet, to thesemiconductor wafer.

When the formation of the modified sections is performed before theaffixing steps, the affixing steps are preferably performed with thesemiconductor wafer supported, in order to prevent the semiconductorwafer from breaking as a result of the stress applied to thesemiconductor wafer during the affixing process.

When the formation of the modified sections is performed after theaffixing steps, if a die bonding film and a dicing tape, or a dicing-diebonding integrated sheet, which transmit the laser beam are used, thenirradiation of the laser beam can also be performed from the rearsurface of the semiconductor wafer.

(Step (IIA))

Next, the dicing tape 3 is expanded with the laminate 6 in a cooledstate (step (IIA)). The expression “with the laminate in a cooled state”means a state in which the temperature of the laminate is lower thanroom temperature. It does not matter whether or not the expansion isbeing performed while the laminate is being cooled. The dicing tape maybe expanded after the laminate has already been cooled, or may beexpanded while the laminate is being cooled.

The temperature of the laminate during the expansion is a temperaturelower than room temperature (for example, 25° C.). From the viewpoint ofimproving the divisibility of the die bonding film, the temperature ofthe laminate is, for example, preferably not higher than 10° C., morepreferably 0° C. or lower, still more preferably −5° C. or lower, andparticularly preferably −10° C. or lower. In terms of the divisibilityof the die bonding film, the temperature of the laminate is preferablyas low as possible. However, from the view point of maintaining apractical level for the mechanical properties of the die bonding filmand the dicing tape, the temperature of the laminate is preferably notlower than −15° C. The temperature of the laminate refers to the valueobtained by measuring the temperature of the upper surface of thesemiconductor wafer or the temperature of the rear surface of the dicingtape (the surface not affixed to the die bonding film).

There are no particular limitations on the cooling method. Examplesinclude methods using a cooling air stream from a chiller, and methodsusing a cooling stage or the like equipped with a cooling device.

The expansion of the dicing tape is performed by applying an externalforce to the dicing tape, and there are no particular limitations on themethod used for performing this expansion. The external force is appliedso that the dicing tape expands in the in-plane direction. In this step,the dicing tape is usually expanded radially.

The expansion performed in the step (IIA) is usually not performed forthe purpose of dividing the semiconductor wafer and the die bonding filminto chips. However, some partial separation into chips along theintended cutting lines may occur. Alternatively, in some cases thesemiconductor wafer may partially separate without any separationoccurring in the die bonding film.

There are no particular limitations on the expansion time. For example,the time is preferably at least 5 seconds, and is preferably not morethan 60 seconds. The expansion time corresponds with the time for whichthe external force is applied.

From the viewpoint of improving the divisibility of the die bondingfilm, the expansion rate is, for example, preferably at least 10mm/second, and more preferably 50 mm/second or greater. Further, fromthe viewpoint of suppressing the problem in which outer peripheralsections of the die bonding film are scattered across the wafer, theexpansion rate is, for example, preferably not more than 400 mm/second,and more preferably 200 mm/second or less.

(Step (IIB))

After the step (IIA), the expanded dicing tape 3 is loosened (step(IIB)). This “loosening of the dicing tape” refers to reducing, oreliminating, the external force applied to the dicing tape in the step(IIA).

When the dicing tape is loosened, the laminate may be either in a cooledstate or an uncooled state. In other words, the temperature of thedicing tape may be a temperature that is lower than room temperature, ormay be a temperature equal to or greater than room temperature. Thedicing tape is usually in a cooled state.

When no other optional steps are included between the step (IIA) and thestep (IIC), the time period from the point where loosening of theexpanded dicing tape is started in the step (IIB) through to the pointwhere expansion of the dicing tape is started again in the step (IIC) istermed the dicing tape loosening time. From the viewpoint ofoperability, or from the viewpoint of maintaining the cooled statedepending on the cooling method that is used, this loosening time is,for example, preferably not longer than 10 seconds, and more preferably5 seconds or less. Further, from the viewpoint of improving thedivisibility of the die bonding film, the loosening time is preferablyat least 1 second.

By loosening the dicing tape, the expanded dicing tape usuallycontracts. However, in some cases the expanded state may be maintainedso that no contraction occurs. In the step (IIB), the dicing tape mayeither contract, or be held in the expanded state.

(Step (IIC))

Subsequently, the dicing tape 3 is expanded with the laminate 6 in acooled state, thereby dividing the semiconductor wafer 1 and the diebonding film 2 into chips 7 along the intended cutting lines 4, andwidening the spaces between the chips 7 (step (IIC)). The expression“with the laminate in a cooled state” describes the same state as thatin the aforementioned step (IIA). Further, in the same manner as thestep (IIA), the expansion of the dicing tape is performed by applying anexternal force to the dicing tape, but there are no particularlimitations on the method used for performing this expansion. Theexternal force is applied so that the dicing tape expands in thein-plane direction. In this step, the dicing tape is usually expandedradially.

In the step (IIC), by expanding the dicing tape, the semiconductor waferand the die bonding film are divided into chips along the intendedcutting lines, and the spaces between the chips are widened. Althoughthere are no particular limitations on the space between chips (alsoreferred to as the “kerf width”), from the viewpoint of the pickupproperties in the subsequent pickup step, the space is preferably atleast 10 μm, more preferably 30 μm or greater, and still more preferably50 μm or greater.

There are no particular limitations on the expansion time. For example,the time is preferably at least 5 seconds, and is preferably not morethan 60 seconds. The expansion time corresponds with the time for whichthe external force is applied.

From the viewpoint of improving the divisibility of the die bondingfilm, the expansion rate is, for example, preferably at least 10mm/second, and more preferably 50 mm/second or greater. Further, fromthe viewpoint of suppressing the problem in which outer peripheralsections of the die bonding film are scattered across the wafer, theexpansion rate is, for example, preferably not more than 400 mm/second,and more preferably 200 mm/second or less.

From the viewpoint of improving the divisibility, the external forceapplied to the dicing tape in the step (IIC) is preferably larger thanthe force applied to the dicing tape in the step (IIA).

The steps of expanding and then loosening the dicing tape may berepeated. In other words, following the step (I), the preparation may beconducted in accordance with a sequence represented by step (IIA)→step(IIB)→step (IIA)→step (IIB)→step (IIC).

A commercially available expansion apparatus can be used for performingstep (IIA) to step (IIC). Examples of the expansion apparatus include anapparatus “MAE300” (manufactured by Tokyo Seimitsu Co., Ltd.) and a “DieSeparator DDS2300” (manufactured by DISCO Corporation).

By performing the steps of expanding, loosening, and then once againexpanding the dicing tape, the extensibility of the dicing tape isimproved, and even if the laminate is in a cooled state, the dicing tapecan be expanded satisfactorily, enabling division of the semiconductorwafer and the die bonding film to be performed favorably.

In the stealth dicing method, it is thought that the cutting of thesemiconductor wafer and the die bonding film proceeds in the followingmanner. First, when the dicing tape is expanded, an external force isapplied to the semiconductor wafer, and cracks occur through thethickness direction of the semiconductor wafer, with the modifiedsections inside the semiconductor wafer acting as starting points.Subsequently, these cracks reach through to the upper surface and thelower surface of the semiconductor wafer, and then to the die bondingfilm which is adhered to the semiconductor wafer, causing thesemiconductor wafer and the die bonding film to fracture.

If the dicing tape exhibits superior extensibility, then it is thoughtthat the size of the external force applied to the semiconductor waferincreases, enabling the semiconductor wafer and the die bonding film tobe divided with superior yield.

In the aforementioned conventional expansion method illustrated in FIG.18, when the force pushing upward on the dicing tape 3 is increased inorder to increase the extensibility of the dicing tape 3, variousproblems such as the so-called necking phenomenon or rupture may occur,and achieving satisfactory expansion of the dicing tape 3 is difficult.

Occurrence of the necking phenomenon is particularly marked when adicing tape having low intermolecular interactions is used, such as adicing tape formed from a general-purpose polyolefin-based material suchas polyethylene (PE) or polypropylene (PP). According to the presentembodiment, even if a dicing tape having low intermolecular interactionsis used, the occurrence of the necking phenomenon and rupture can bereduced, and the extensibility of the dicing tape can be improved.

For example, according to the present embodiment, the amount ofexpansion of the dicing tape is preferably at least 1.0 mm, morepreferably at least 1.5 mm, still more preferably at least 2.0 mm, andparticularly preferably 3.0 mm or greater. However, from the viewpointof suppressing rupture of the dicing tape, the amount of expansion ispreferably not more than 6.0 mm. The amount of expansion [mm] is thevalue along a line passing through the center of the dicing tapecalculated using the formula “(length after expansion [mm])−(lengthbefore expansion [mm])”. Although not a particular limitation, the abovenumerical range is particularly suited to the cutting of semiconductorwafers having a diameter that is preferably 200 mm or greater, and morepreferably 300 mm or greater.

The amount of expansion can be measured using the method describedbelow. FIG. 14A illustrates schematic views (plan views andcross-sectional views) of a dicing tape before expansion and a dicingtape after expansion.

(1) A mark A is made on the dicing tape 3 at a position that is adistance L₁/2 [mm] from the center O of the dicing tape 3 beforeexpansion. (FIG. 14A(1)).

(2) A mark B is made in a position having point symmetry relative to themark A about the center O. The distance L₁ [mm] between A and B isdeemed the “length before expansion [mm]” (FIG. 14A(1)).

(3) The dicing tape 3 is expanded using the expansion method of thepresent embodiment.

(4) A distance L₂ [mm] between A and B in the dicing tape 3 after theexpansion is measured and deemed the “length after expansion [mm]” (FIG.14A(2)).

(5) The amount of expansion [mm] is determined from “(length afterexpansion [mm])−(length before expansion [mm])”.

It is preferable that the amount of expansion determined in an arbitrarydirection of the dicing tape satisfies the above range, and it isparticularly preferable that the average value of the amounts ofexpansion determined in the MD direction and the TD direction of thedicing tape satisfies the above range.

Further, according to the present embodiment, the expansion ratio forthe dicing tape following the step (IIC) can, for example, preferably beset to at least 1.0%, more preferably at least 1.5%, still morepreferably at least 2.0%, and particularly preferably 3.0% or greater.However, from the viewpoint of suppressing rupture of the dicing tape,the expansion ratio is preferably not more than 3.0%, and morepreferably 2.0% or less. The expansion ratio [%] is a value determinedalong a line passing through the center of the dicing tape using theformula “(amount of expansion [mm])/(length before expansion [mm])×100”.Although not a particular limitation, this numerical range isparticularly suited to semiconductor wafers having a diameter that ispreferably 200 mm or greater, and more preferably 300 mm or greater. The“amount of expansion [mm]” and the “length before expansion [mm]” are asdefined above.

It is preferable that the expansion ratio determined in an arbitrarydirection of the dicing tape satisfies the above range, and it isparticularly preferable that the average value of the expansion ratiosdetermined in the MD direction and the TD direction of the dicing tapesatisfies the above range.

When measuring the amount of expansion and the expansion ratio, thelength before expansion may be set appropriately in accordance with thesize of the semiconductor wafer being cut, namely the size of thesemiconductor wafer to which the dicing tape is affixed. For example, inthe case of a dicing tape used for dividing a semiconductor wafer havinga diameter D [mm], it is preferable that the amount of expansion and theexpansion ratio measured using a value of (D−5) to (D+5) as the distanceL₁ [mm] between the marks A and B satisfy the respective rangesdescribed above. In a specific example, in the case of a dicing tapeused on a semiconductor wafer having a diameter of 300 mm, the amount ofexpansion and the expansion ratio when L₁=250 mm preferably satisfy therespective ranges described above.

Evaluation of the amount of expansion and the expansion ratio of thedicing tape may also be performed using a dicing-die bonding integratedsheet instead of the dicing tape. If a dicing-die bonding integratedsheet is expanded in a stand-alone state not laminated to asemiconductor wafer, then because no cracking start points exist, thedie bonding film usually does not fracture, but is rather expandedtogether with the dicing tape. Even in those cases where the die bondingfilm is also expanded, the amount of expansion and the expansion ratioof the dicing-die bonding integrated sheet can be used as the amount ofexpansion and the expansion ratio for the dicing tape.

Comparing the present embodiment with a conventional expansion method,if the external force applied in the step (IIC) and the external forceapplied in the conventional expansion method are set to the same level,then the amount of expansion and the expansion ratio for the dicing tapecan be increased in the present embodiment by at least 1.5-fold, andpreferably at least 2-fold.

The present embodiment provides a superior expansion method whichenables the extensibility of a commercially available dicing tape to beimproved via simple steps, without using any special equipment, andwithout requiring any complex steps. By using the expansion method ofthe present embodiment, a semiconductor wafer and a die bonding film canbe cut favorably.

Second Embodiment

The second embodiment relates to an expansion method comprising: a step(Ia) of preparing a laminate having a semiconductor wafer in whichmodified sections have been formed along intended cutting lines, a diebonding film, a dicing tape and a frame; a step (Ib) of supplying thelaminate to the top of a height-adjustable expansion stage of anexpansion apparatus comprising the expansion stage and a fasteningmember capable of fastening the frame; a step (Ic) of fastening theframe using the fastening member; a step (IIa) of raising the expansionstage and expanding the dicing tape with the laminate in a cooled state;a step (IIb) of lowering the raised expansion stage and loosening theexpanded dicing tape; and a step (IIc) of raising the expansion stageand expanding the dicing tape with the laminate in a cooled state,dividing the semiconductor wafer and the die bonding film into chipsalong the intended cutting lines, and widening the spaces between thechips.

FIG. 6A and FIG. 6B are schematic diagrams illustrating this embodimentof the expansion method, and FIG. 9 is a flowchart illustrating thisembodiment of the expansion method. In the present embodiment, anexpansion apparatus is used which comprises a height-adjustableexpansion stage and a fastening member capable of fastening the frame.Where applicable, the description relating to the first embodiment canalso be applied to the present embodiment.

(Step (Ia))

First, a laminate 6′ having a semiconductor wafer 1 in which modifiedsections 5 have been formed along intended cutting lines 4, a diebonding film 2, a dicing tape 3 and a frame 9 is prepared (step (Ia),step S1). The laminate 6′ in the present embodiment has the frame 9 inaddition to the semiconductor wafer 1 in which the modified sections 5have been formed along the intended cutting lines 4, the die bondingfilm 2 and the dicing tape 3.

FIG. 8 is a schematic plan view illustrating an embodiment of thelaminate 6′. The frame 9 is affixed to the surface of the dicing tape 3to which the semiconductor wafer 1 and the die bonding film 2 arelaminated. The frame may also be affixed to the surface of the dicingtape 3 opposite the surface to which the semiconductor wafer 1 and thedie bonding film 2 are laminated. A rigid ring-shaped frame is usuallyused as the frame 9. There are no particular limitations on the frame 9,and examples include frames formed from metal materials such asstainless steel or aluminum, and frames formed from resin materials suchas polycarbonate. A conventionally known frame typically used in adicing step may be selected appropriately as the frame 9, in accordancewith the size of the semiconductor wafer 1.

(Step (Ib))

Next, the laminate 6′ is supplied to the top of a height-adjustableexpansion stage 10 of an expansion apparatus comprising the expansionstage 10 and a fastening member 11 capable of fastening the frame (step(Ib), step S2). The expansion stage 10 is a circular cylindrical stagehaving a larger diameter than the semiconductor wafer 1 and a smallerdiameter than the frame 9, and can be raised and lowered. The expansionstage 10 may also include an internal or external cooling device (notshown in the figures). The fastening member 11 is a member capable offastening the frame 9 in a prescribed position, and there are noparticular limitations on the shape of the member. For example, a memberhaving a shape capable of clamping the frame 9 from above and below maybe used. The expansion stage 10 is disposed so that upper surface of thestage is positioned at the same height as, or lower than, the rearsurface (the dicing tape-side surface) of the laminate 6′ that issupplied to the expansion apparatus.

As illustrated in FIG. 6A, when the laminate 6′ is supplied, the frame 9is supported by the fastening member 11. Depending on the position inwhich the expansion stage 10 is disposed, the embodiment upon supply ofthe laminate 6′ to the top of the expansion stage 10 includes both theembodiment in which the expansion stage 10 and the laminate 6′ are incontact and the embodiment in which the expansion stage 10 and thelaminate 6′ are not in contact. The latter case is illustrated in FIG.6A. In both of these embodiments, the laminate 6′ is supplied so thatthe semiconductor wafer 1 is positioned within the diameter of theexpansion stage 10.

(Step (Ic))

Following supply of the laminate 6′ to the top of the expansion stage10, the frame 9 is fastened with the fastening member 11 (step (Ic),step S3). In FIG. 6A, the frame 9 is clamped by the fastening member 11.

(Step (IIa))

Subsequently, by raising the expansion stage 10 and pushing the dicingtape 3 upward with the laminate 6′ in a cooled state, the dicing tape 3is expanded radially (step (IIa), step S4). There are no particularlimitations on the cooling method, but in the case where the expansionstage 10 is equipped with a cooling device (not shown in the figures),the laminate 6′ is brought into close proximity with, or into contactwith, the expansion stage 10, thereby lowering the temperature of thelaminate 6′ to a temperature lower than room temperature, and placingthe laminate 6′ in a cooled state.

When the expansion stage 10 is equipped with a cooling device, from theviewpoint of improving the divisibility of the die bonding film, thetemperature of the upper surface of the expansion stage 10 is preferablynot higher than 10° C., more preferably 0° C. or lower, still morepreferably −5° C. or lower, and particularly preferably −10° C. orlower.

Commercially available expansion apparatus are generally provided with adevice which can preset the raising distance for the expansion stage 10.From the viewpoint of improving the divisibility of the die bondingfilm, the set value in this device (also referred to as the “raisingdistance setting”) is preferably at least 5 mm, more preferably 7 mm orgreater, and still more preferably 10 mm or greater. Further, from theviewpoint of inhibiting rupture of the dicing tape, the raising distancesetting is, for example, preferably not more than 15 mm. In acommercially available expansion apparatus, if the expansion stage 10 israised in a state without the laminate 6′ supplied to the top of theexpansion stage 10, then the raising distance prescribed by the “raisingdistance setting” is usually obtained. The raising distance setting is aset value represented by “(total distance raised for expansion stage10)−(distance raised to bring expansion stage 10 into contact with rearsurface of laminate 6′)” (h₁ in FIG. 6A, h₂ in FIG. 6B).

Further, commercially available expansion apparatus are generallyprovided with a device which can preset the speed with which theexpansion stage 10 is raised. From the viewpoint of improving thedivisibility of the die bonding film, the set value in this device (alsoreferred to as the “raising speed setting”) is preferably at least 10mm/second, and more preferably 50 mm/second or greater. Further, fromthe viewpoint of suppressing the problem in which outer peripheralsections of the die bonding film are scattered across the wafer, theraising speed setting is, for example, preferably not more than 400mm/second, and more preferably 200 mm/second or less. In a commerciallyavailable expansion apparatus, if the expansion stage 10 is raised in astate without the laminate 6′ supplied to the top of the expansion stage10, then the raising speed prescribed by the “raising speed setting” isusually obtained.

(Step (IIb))

Following the step (IIa), the raised expansion stage 10 is lowered, andthe expanded dicing tape 3 is loosened (step (IIb), step S5). Theexpansion stage 10 may be lowered to its original position, namely thesame position as that before the raising process, or may be lowered toan arbitrary position partway between the raised position and theoriginal position. As illustrated in FIG. 6B, the expansion stage 10 ispreferably lowered to its original position.

(Step (IIc))

Subsequently, by raising the expansion stage 10 and pushing the dicingtape 3 upward with the laminate 6′ in a cooled state, the dicing tape 3is expanded radially. As a result, the semiconductor wafer 1 and the diebonding film 2 are divided into chips 7 along the intended cutting lines4, and the spaces between the chips are widened (step (IIc), step S6).The cooling method is the same as that described above for the step(IIa).

From the viewpoint of improving the divisibility of the die bondingfilm, the raising distance setting for the expansion stage 10 is, forexample, preferably at least 5 mm, more preferably 7 mm or greater, andstill more preferably 10 mm or greater. Further, from the viewpoint ofinhibiting rupture of the dicing tape, the raising distance setting is,for example, preferably not more than 18 mm, and more preferably 15 mmor less.

Furthermore, from the viewpoint of improving the divisibility of the diebonding film, the raising speed setting for the expansion stage 10 ispreferably at least 10 mm/second, and more preferably 50 mm/second orgreater. Further, from the viewpoint of suppressing the problem in whichouter peripheral sections of the die bonding film are scattered acrossthe wafer, the raising speed setting is, for example, preferably notmore than 400 mm/second, and more preferably 200 mm/second or less.

Although not a particular limitation, the raising distance setting andthe raising speed setting in the step (IIa) and the step (IIc) areparticularly suited to semiconductor wafers having a diameter that ispreferably 200 mm or greater, and more preferably 300 mm or greater. Theraising distance setting and the raising speed setting may be determinedappropriately with due consideration of factors such as the diameter ofthe semiconductor wafer, the diameter of the expansion stage, the chipsize, and the kerf width.

In the present embodiment, from the viewpoint of improving thedivisibility of the die bonding film, the raising distance setting forthe expansion stage 10 in the step (IIe) is preferably the same as, orgreater than, the raising distance setting for the expansion stage 10 inthe step (IIa). The raising distance setting for the expansion stage 10in the step (a) is preferably set to a value that is at least 1.0 times,more preferably at least 1.5 times, and still more preferably at least2.0 times, the raising distance setting for the expansion stage 10 inthe step (IIa).

(Step (IId))

Following the step (IIc), a step may be provided for maintaining theexpanded state of the dicing tape 3 (step (IId), step S7). Examples ofthe method used for maintaining the expanded state include a method inwhich the dicing tape 3 is affixed to a separate frame from the frame 9,and a method in which the portions of the dicing tape 3 positionedoutside the semiconductor wafer 1 are subjected to heat shrinkage. Thereare no particular limitations on the heating temperature for the dicingtape when performing the heat shrinkage, and for example a temperatureof 80° C. may be used.

Third Embodiment

The third embodiment relates to an expansion method comprising: a step(Ia′) of preparing a laminate having a semiconductor wafer in whichmodified sections have been formed along intended cutting lines, a diebonding film, a dicing tape and a frame; a step (Ib′) of supplying thelaminate to the top of a height-adjustable expansion ring of anexpansion apparatus comprising the expansion ring and a fastening membercapable of fastening the frame; a step (Ic′) of fastening the frameusing the fastening member; a step (IIa′) of raising the expansion ringand expanding the dicing tape with the laminate in a cooled state; astep (IIb′) of lowering the raised expansion ring and loosening theexpanded dicing tape; and a step (IIc′) of raising the expansion ringand expanding the dicing tape with the laminate in a cooled state,dividing the semiconductor wafer and the die bonding film into chipsalong the intended cutting lines, and widening the spaces between thechips.

FIG. 7A and FIG. 7B are schematic diagrams illustrating this embodimentof the expansion method. In the present embodiment, an expansionapparatus is used which comprises a height-adjustable expansion ring anda fastening member capable of fastening the frame. This embodimentdiffers from the second embodiment in the use of the height-adjustableexpansion ring instead of the aforementioned height-adjustable expansionstage. The step (Ia′) is the same as the step (Ia). Where applicable,the descriptions relating to the first and second embodiments can alsobe applied to the present embodiment, and the description relating tothe expansion stage in the second embodiment can also be applied to theexpansion ring.

(Step (Ib))

In the present embodiment, the laminate 6′ is supplied to the top of aheight-adjustable expansion ring 12 of an expansion apparatus comprisingthe expansion ring 12 and a fastening member 11 capable of fastening theframe (step (Ib′)). The expansion ring 12 is a ring having a largerinner diameter than the semiconductor wafer 1 and a smaller outerdiameter than the frame 9, and can be raised and lowered. The expansionring 12 is disposed so that upper surface of the ring is positioned atthe same height as, or lower than, the rear surface (the dicingtape-side surface) of the laminate 6′ that is supplied to the expansionapparatus.

As illustrated in FIG. 7A, when the laminate 6′ is supplied, the frame 9is supported by the fastening member 11. Depending on the position inwhich the expansion ring 12 is disposed, the embodiment upon supply ofthe laminate 6′ to the top of the expansion stage 10 includes both theembodiment in which the expansion ring 12 and the laminate 6′ are incontact and the embodiment in which the expansion ring 12 and thelaminate 6′ are not in contact. The former case is illustrated in FIG.7A. In both of these embodiments, the laminate 6′ is supplied so thatthe semiconductor wafer 1 is positioned inside the outer diameter of theexpansion ring 12.

(Step (Ic′))

Following supply of the laminate to the top of the expansion ring 12,the frame 9 is fastened with the fastening member 11 (step (Ic)). InFIG. 7A, the frame 9 is clamped by the fastening member 11.

(Step (IIa′))

Subsequently, by raising the expansion ring 12 and pushing the dicingtape 3 upward with the laminate 6′ in a cooled state, the dicing tape 3is expanded radially (step (IIa′)). There are no particular limitationson the cooling method, and in one example, a cooling stage 10′ fittedwith a cooling device is provided inside the expansion ring 12, andcooling is performed using the cooling stage 10′. By bringing thelaminate 6′ into close proximity with, or into contact with, the coolingstage 10′, the temperature of the laminate 6′ is lowered to atemperature lower than room temperature, and the laminate 6′ is placedin a cooled state.

The temperature of the upper surface of the cooling stage 10′ ispreferably set within the same range as that described above for thetemperature of the upper surface of the expansion stage 10 in the secondembodiment.

(Step (IIb′))

Following the step (IIa′) the raised expansion ring 12 is lowered, andthe expanded dicing tape 3 is loosened (step (IIb′)).

(Step (IIc′))

Subsequently, by raising the expansion ring 12 and pushing the dicingtape 3 upward with the laminate in a cooled state, the dicing tape 3 isexpanded radially. As a result, the semiconductor wafer 1 and the diebonding film 2 are divided into chips 7 along the intended cutting lines4, and the spaces between the chips are widened (step (IIc′)). Thecooling method is the same as that described above for the step (IIa′).

Step (IId′))

Following the step (IIc′), a step may be provided for maintaining theexpanded state of the dicing tape 3 (step (IId′)).

Fourth Embodiment

The fourth embodiment relates to a method for manufacturing asemiconductor device comprising: a step (I) of preparing a laminatehaving a semiconductor wafer in which modified sections have been formedalong intended cutting lines, a die bonding film and a dicing tape; astep (II) of expanding the dicing tape, dividing the semiconductor waferand the die bonding film into chips along the intended cutting lines,and widening the spaces between the chips; a step (III) of picking up achip from the dicing tape; and a step (IV) of die bonding the chip to anadherend, wherein the step (I) and the step (II) are performed using theexpansion method of one of the embodiments described above.

The present embodiment has the steps (I) to (IV) in this order. Theembodiment may also include other optional steps before or after eachstep, such as a step of detaching a protective sheet, a transport step,an inspection or verification step, a wire bonding step, or a moldingstep. The step (I) and the step (II) are the same as the aforementionedsteps (I) to (IIC), steps (Ia) to (IIc), or steps (Ia′) to (IIc′).

(Step (III))

Following division of the semiconductor wafer 1 and the die bonding film2 into chips, a chip 7 is picked up from the dicing tape 3 (step (III)).FIG. 10 is a schematic diagram illustrating an embodiment of this pickupstep. In FIG. 10, a collet 13 and a needle 14 are used to detach thechip 7 from the dicing tape 3, thus obtaining a single chip 7 (asemiconductor chip 7 a and an individual piece of the die bonding film 7b bonded to the semiconductor chip).

When an ultraviolet-curable adhesive is used for the dicing tape, thedicing tape may be irradiated with ultraviolet light prior to performingthe step (III) to cure the ultraviolet-curable adhesive. This reducesthe adhesive strength between the dicing tape and the die bonding film,enabling the detachment between the dicing tape and the die bonding filmto proceed more easily.

(Step (IV))

Next, the chip 7 is die bonded to an adherend 15 (step (IV)). FIG. 11 isa schematic diagram illustrating an embodiment of this die bonding step.In FIG. 11, the collet 13 is used to mount the chip 7 on the adherend 15so that the die bonding film 7 b contacts the adherend 15. Followingmounting of the chip 7 on the adherend 15, the die bonding film isusually heated and cured.

According to this embodiment, a semiconductor device can be manufacturedefficiently via simple steps, without using any special equipment, andwithout requiring any complex steps.

Fifth Embodiment

The fifth embodiment relates to a semiconductor device having anadherend, and a chip bonded to the adherend, wherein the semiconductordevice is manufactured using the method for manufacturing asemiconductor device according to the embodiment described above.

Examples of the adherend include a semiconductor chip-mounting supportmember, or another semiconductor chip or the like. Specific examples ofthe semiconductor device include a semiconductor device in which atleast one semiconductor chip is mounted to a semiconductor chip-mountingsupport member, and the semiconductor chip and the semiconductorchip-mounting support member are bonded together via a die bonding film(FIG. 12), and a semiconductor device in which at least twosemiconductor elements are mounted on a semiconductor chip-mountingsupport member, and the semiconductor chip-mounting support member and asemiconductor chip, and the two semiconductor chips are bonded togethervia die bonding films (FIG. 13).

Examples of the semiconductor chip-mounting support member include leadframes such as a 42-alloy lead frame or a copper lead frame, plasticfilms formed from a polyimide resin or an epoxy resin or the like,plastics such as a polyimide resin or an epoxy resin that have beenreinforced with a glass non-woven cloth base material, ceramics such asalumina, organic substrates having an organic resist layer provided onthe surface, and organic substrates with wiring formed thereon. Here,the term “organic substrate” mainly means a substrate composed of anorganic material such as a resin, a thermoplastic resin or athermosetting resin, which has been reinforced with glass fiber.

FIG. 12 is a schematic cross-sectional view illustrating one embodimentof the semiconductor device. In the semiconductor device 21 illustratedin FIG. 12, a semiconductor chip 7 a is bonded to a semiconductorchip-mounting support member 22 via a die bonding film 7 b. Theconnection terminals (not shown in the figure) of the semiconductor chip7 a are connected electrically to external connection terminals (notshown in the figure) via wires 23. Moreover, the semiconductor chip 7 aand the wires 23 and the like are encapsulated by a sealing material 24.

FIG. 13 is a schematic cross-sectional view illustrating anotherembodiment of the semiconductor device. The semiconductor device 21′illustrated in FIG. 13 is a 3D-packaged semiconductor device(Stacked-PKG) having a structure in which a plurality of semiconductorchips 7 a are laminated on top of a semiconductor chip-mounting supportmember 22. In FIG. 13, the semiconductor chip 7 a of the first level isbonded to the semiconductor chip-mounting support member 22 via a diebonding film 7 b. Another semiconductor chip 7 a is then bonded on topof the first semiconductor chip 7 a via a die bonding film 7 b.Moreover, the entire structure is encapsulated by a sealing material 24.The connection terminals (not shown in the figure) of the semiconductorchips 7 a are connected electrically to external connection terminals 25via wires 23.

The semiconductor device of the present embodiment can be manufacturedefficiently via simple manufacturing steps, using a commerciallyavailable die bonding film.

Embodiments of the present invention have been described above withreference to the drawings, but the present invention is in no waylimited by the embodiments described above. For example, in the secondembodiment and the third embodiment described above, examples werepresented in which the dicing tape was expanded by raising an expansionstage or an expansion ring, but the dicing tape may instead be expandedby lowering a fastening member which is capable of fastening the frame.Further, in each of the embodiments, the shapes and materials and thelike of the members described above such as the laminate, the expansionstage, the expansion ring and the fastening member can be altered asapplicable.

EXAMPLE

Next, the invention is described based on a series of examples, but thepresent invention is in no way limited by these examples.

Example 1

A die bonding film (DAF) (thermosetting epoxy resin-containing adhesive,thickness: 20 μM, diameter 335 mm) having a removable base material(polyethylene terephthalate film, thickness: 38 μm), and a dicing tape(DCT) composed of a base film (polyolefin-based film, thickness: 80 μm,diameter: 370 mm) and an adhesive (pressure-sensitive adhesive,thickness: 20 μm) were bonded together so that the die bonding film andthe adhesive made contact, thus obtaining a dicing-die bondingintegrated sheet.

[Evaluation]

Using the thus obtained dicing-die bonding integrated sheet, theextensibility of the dicing tape when cooled was evaluated. FIG. 14Billustrates a schematic plan view of the dicing-die bonding integratedsheet used in the evaluation. Following removal of the removable basematerial, a ring-shaped frame (inner diameter: 350 mm) was affixed tothe dicing-die bonding integrated sheet.

Using a permanent marker pen, marks were made at locations 50 mm, 75 mmand 125 mm from the center of the dicing-die bonding integrated sheet inthe MD direction (Machine Direction, the flow direction of the film) ofthe base film. For each distance, two marks were made at locations oneither side of the center. Accordingly, the distance between each set oftwo marks was 100 mm, 150 mm and 250 mm respectively. These distancesrepresent the “length before expansion”.

Similarly, a permanent marker pen was also used to make marks atlocations 50 mm, 75 mm and 125 mm from the center of the dicing-diebonding integrated sheet in the TD direction (Transverse Direction, thewidth direction of the film) of the base film.

An expansion was performed using the same method as that illustrated insteps (IIa) to (IIc) of FIGS. 6A and 6B, but with the exception of notlaminating a semiconductor wafer to the dicing-die bonding integratedsheet. Specifically, the dicing tape was expanded using an expansionapparatus (manufactured by Hitachi Chemical Co., Ltd.) having aheight-adjustable expansion stage (diameter: 345 mm) equipped with acooling device, and a fastening member capable of fastening thering-shaped frame. When fastening the ring-shaped frame using thefastening member, the center of the dicing-die bonding integrated sheetwas aligned with the center of the expansion stage. Because asemiconductor wafer was not used, the die bonding film was not cut, butwas rather expanded together with the dicing tape.

The expansion conditions were as follows.

Step (IIa):

Raising distance setting for expansion stage: 8 mm (h₁)

Raising speed setting for expansion stage: 100 mm/second

Temperature of upper surface of expansion stage: −10° C.

Surface temperature of dicing-die bonding integrated sheet: −10° C.

Step (Iib):

Dicing tape loosening time: 1 second

Step (IIc):

Raising distance setting for expansion stage: 15 mm (h₂)

Raising speed setting for expansion stage: 100 mm/second

Temperature of upper surface of expansion stage: 0° C.

Surface temperature of dicing-die bonding integrated sheet: 0° C.

The temperature of the upper surface of the expansion stage and thesurface temperature of the dicing-die bonding integrated sheet weremeasured using a laser thermometer (“Non-Contact Radiation Thermometer”,manufactured by A&D Co., Ltd.).

After performing the step (IIc), the distance between each set of twomarks across the center of the dicing-die bonding integrated sheet wasmeasured (0.5 mm increments) for both the MD direction and the TDdirection. These distances represent the “length after expansion”. Usingthe “length before expansion” and the “length after expansion”, theamount of expansion and the expansion ratio were determined. Theevaluation results are shown in Table 1.

The amount of expansion [mm], in both the MD direction and the TDdirection, was the value determined by calculating “(length afterexpansion [mm])−(length before expansion [mm])”, and the average amountof expansion represents the arithmetic mean of the amounts of expansionin the MD direction and the TD direction. Further, the expansion ratio[%], in both the MD direction and the TD direction, was the valuedetermined by calculating “(amount of expansion [mm])/(length beforeexpansion [mm])×100”, and the average expansion ratio represents thearithmetic mean of the expansion ratios in the MD direction and the TDdirection.

Comparative Example 1

With the exception of altering the expansion method, the extensibilityof a dicing tape was evaluated in the same manner as Example 1. InComparative Example 1, the expansion was performed in accordance withthe method illustrated in step (ii) of FIG. 18, but with the exceptionof not laminating a semiconductor wafer to the dicing-die bondingintegrated sheet. Specifically, the dicing tape was expanded using anexpansion apparatus (manufactured by Hitachi Chemical Co., Ltd.) havinga height-adjustable expansion stage equipped with a cooling device, anda fastening member capable of fastening the ring-shaped frame.

The expansion conditions were as follows.

Step (ii):

Raising distance setting for expansion stage: 15 mm

Raising speed setting for expansion stage: 100 min/second

Temperature of upper surface of expansion stage: 0° C.

Surface temperature of dicing-die bonding integrated sheet: 0° C.

TABLE 1 Surface Raising temperature distance Length before Length afterAmount of expansion of integrated setting for expansion expansion(expansion ratio) sheet stage MD TD MD TD MD [mm] TD [mm] average [mm][° C.] [mm] [mm] [mm] [mm] [mm] (MD [%]) (TD [%]) (average [%]) Example1 (IIa): −10 (IIa): 8 100 100 102 102 2.0 2.0 2.0 (IIc): 0 (IIc): 15(2.0) (2.0) (2.0) 150 150 152 152.5 2.0 2.5 2.3 (1.3) (1.7) (1.5) 250250 254.5 254 4.5 4.0 4.3 (1.8) (1.6) (1.7) Comparative (ii): 0 (ii): 15100 100 101 101 1.0 1.0 1.0 Example 1 (1.0) (1.0) (1.0) 150 150 150.5151.5 0.5 1.5 1.0 (0.3) (1.0) (0.7) 250 250 252 251.5 2.0 1.5 1.8 (0.8)(0.6) (0.7)

As shown in Table 1, by using the expansion method according to theembodiment of the present invention, the extensibility of the dicingtape was able to be increased.

Example 2

A dicing-die bonding integrated sheet was obtained in the same manner asExample 1. Further, a silicon wafer (thickness: 50 μm, diameter: 300 mm)was processed with a laser dicing saw “DFL7360” (manufactured by DISCOCorporation) in accordance with the laser processing conditionsdescribed above, thus obtaining a silicon wafer having modified sectionsformed along intended cutting lines (spacing between lines: 10 mm)Subsequently, the dicing-die bonding integrated sheet from which theremovable base material had been removed was affixed to the siliconwafer so that the die bonding film and the rear surface of the siliconwafer made contact. Moreover, a ring-shaped frame (inner diameter: 350mm) was affixed to the dicing-die bonding integrated sheet to obtain alaminate such as that illustrated in FIG. 8.

[Evaluation]

Using the thus obtained laminate, the divisibility of the semiconductorwafer and the die bonding film was evaluated. The evaluation results areshown in Table 2. A photograph of the semiconductor wafer is shown inFIG. 15.

An expansion was performed using the same method as that illustrated insteps (IIa) to (IIc) of FIGS. 6A and 6B. Specifically, the dicing tapewas expanded using an expansion apparatus “Die Separator DDS2300”(manufactured by Disco Corporation) having a height-adjustable expansionstage (diameter: 330 mm) equipped with a cooling device, and a fasteningmember capable of fastening the ring-shaped frame. When fastening thering-shaped frame using the fastening member, the center of thesemiconductor wafer was aligned with the center of the expansion stage.After the expansion, the portions of the dicing tape positioned outsidethe semiconductor wafer were heat shrunk (dicing tape temperature: 80°C.).

The expansion conditions were as follows.

Step (IIa):

Raising distance setting for expansion stage: 8 mm (h₁)

Raising speed setting for expansion stage: 100 mm/second

Temperature of upper surface of expansion stage: −10° C.

Step (IIb):

Dicing tape loosening time: 1 second

Step (IIc):

Raising distance setting for expansion stage: 12 mm (h₂)

Raising speed setting for expansion stage: 100 mm/second

Temperature of upper surface of expansion stage: −10° C.

The temperature of the upper surface of the expansion stage was measuredusing a laser thermometer (“Non-Contact Radiation Thermometer”,manufactured by A&D Co., Ltd.).

After performing the step (IIc), the cutting ratio for the semiconductorwafer and the die bonding film was evaluated. The cutting ratio [%] forthe semiconductor wafer and the die bonding film was determined bycalculating “(number of cut lines)/(total number of lines)×100”. Here,the “total number of lines” is the combined total of all of the intendedcutting lines, and the “number of cut lines” is the total number oflines in which the semiconductor wafer has divided along the entirelength of the intended cutting line and a kerf width of at least 10 μmhas been obtained.

Example 3

With the exception of altering the expansion conditions, a dicing tapewas expanded, and a semiconductor wafer and a die bonding film weredivided and evaluated in the same manner as that described for Example2. The evaluation results are shown in Table 2, and a photograph of thesemiconductor wafer is shown in FIG. 16.

The expansion conditions were as follows.

Step (IIa):

Raising distance setting for expansion stage: 8 mm (h₁)

Raising speed setting for expansion stage: 100 mm/second

Temperature of upper surface of expansion stage: −10° C.

Step (IIIb):

Dicing tape loosening time: 1 second

Step (IIc):

Raising distance setting for expansion stage: 15 mm (h₂)

Raising speed setting for expansion stage: 100 mm/second

Temperature of upper surface of expansion stage: −10° C.

Comparative Example 2

With the exception of altering the expansion method, a dicing tape wasexpanded, and a semiconductor wafer and a die bonding film were dividedand evaluated in the same manner as that described for Example 2. InComparative Example 2, the expansion was performed in accordance withthe method illustrated in step (ii) of FIG. 18. The evaluation resultsare shown in Table 2, and a photograph of the semiconductor wafer isshown in FIG. 17.

The expansion conditions were as follows.

Step (ii):

Raising distance setting for expansion stage: 15 mm

Raising speed setting for expansion stage: 100 mm/second

Temperature of upper surface of expansion stage: −10° C.

TABLE 2 Temperature of upper Raising distance Cutting surface of stagesetting for stage ratio [° C.] [mm] [%] Example 2 (IIa): −10 (IIa): 8 57(IIc): −10 (IIc): 12 Example 3 (IIa): −10 (IIa): 8 87 (IIc): −10 (IIc):15 Comparative (ii): −10 (ii): 15 37 Example 2

As shown in Table 2, by using the expansion method according to anembodiment of the present invention, the cutting ratio for thesemiconductor wafer and the die bonding film was able to be increased.By using the expansion method according to an embodiment of the presentinvention, the semiconductor wafer and the die bonding film were able tobe divided with good yield, enabling a semiconductor device to bemanufactured with good efficiency.

REFERENCE SIGNS LIST

-   1: Semiconductor wafer-   1 a: Surface on which circuit is formed-   1 b: Surface on which no circuit is formed-   2: Die bonding film-   3: Dicing tape-   4: Intended cutting line-   5: Modified section-   6, 6′: Laminate-   7: Chip-   7 a: Semiconductor chip-   7 b: Individual piece of die bonding film-   8: Dicing-die bonding integrated sheet-   9: Frame-   10: Expansion stage-   10′: Cooling stage-   11: Fastening member-   12: Expansion ring-   13: Collet-   14: Needle-   15: Adherend-   21, 21′: Semiconductor device-   22: Semiconductor chip-mounting support member-   23: Wire-   24: Sealing material-   25: External connection terminal-   O: Center of die bonding film-   A, B: Mark-   L₁: Length before expansion-   L₂: Length after expansion-   h₁: Raising distance for expansion stage (step (IIa))-   h₂: Raising distance for expansion stage (step (IIc))

1. An expansion method comprising: a step (I) of preparing a laminatehaving a semiconductor wafer in which modified sections have been formedalong intended cutting lines, a die bonding film and a dicing tape, astep (IIA) of expanding the dicing tape with the laminate in a cooledstate, a step (IIB) of loosening the expanded dicing tape, and a step(IIC) of expanding the dicing tape with the laminate in a cooled state,dividing the semiconductor wafer and the die bonding film into chipsalong the intended cutting lines, and widening spaces between the chips.2. An expansion method according to claim 1 comprising: a step (Ia) ofpreparing a laminate having a semiconductor wafer in which modifiedsections have been formed along intended cutting lines, a die bondingfilm, a dicing tape and a frame, a step (Ib) of supplying the laminateto a height-adjustable expansion stage of an expansion apparatuscomprising the expansion stage and a fastening member capable offastening the frame, a step (Ic) of fastening the frame using thefastening member, a step (IIa) of raising the expansion stage andexpanding the dicing tape with the laminate in a cooled state, a step(IIb) of lowering the raised expansion stage and loosening the expandeddicing tape, and a step (IIc) of raising the expansion stage andexpanding the dicing tape with the laminate in a cooled state, dividingthe semiconductor wafer and the die bonding film into chips along theintended cutting lines, and widening spaces between the chips.
 3. Anexpansion method according to claim 1 comprising: a step (Ia′) ofpreparing a laminate having a semiconductor wafer in which modifiedsections have been formed along intended cutting lines, a die bondingfilm, a dicing tape and a frame, a step (Ib′) of supplying the laminateto a height-adjustable expansion ring of an expansion apparatuscomprising the expansion ring and a fastening member capable offastening the frame, a step (Ic′) of fastening the frame using thefastening member, a step (IIa′) of raising the expansion ring andexpanding the dicing tape with the laminate in a cooled state, a step(IIb′) of lowering the raised expansion ring and loosening the expandeddicing tape, and a step (IIc′) of raising the expansion ring andexpanding the dicing tape with the laminate in a cooled state, dividingthe semiconductor wafer and the die bonding film into chips along theintended cutting lines, and widening spaces between the chips.
 4. Theexpansion method according to claim 1, wherein expansion of the dicingtape is performed by applying an external force to the dicing tape, andan external force applied to the dicing tape in the step (IIC) isgreater than an external force applied to the dicing tape in the step(IIA).
 5. A method for manufacturing a semiconductor device comprising:a step (I) of preparing a laminate having a semiconductor wafer in whichmodified sections have been formed along intended cutting lines, a diebonding film and a dicing tape, a step (II) of expanding the dicingtape, dividing the semiconductor wafer and the die bonding film intochips along the intended cutting lines, and widening spaces between thechips, a step (III) of picking up a chip from the dicing tape, and astep (IV) of die bonding the chip to an adherend, wherein the step (I)and the step (II) are performed using the expansion method according toclaim
 1. 6. A semiconductor device having an adherend, and a chip bondedto the adherend, wherein the semiconductor device is manufactured usingthe method for manufacturing a semiconductor device according to claim5.